The people who work on dartlang.org do try to make it search friendly, of course, but I don't think anyone on the team takes TIOBE very seriously.
According to their chart, C lost half of its popularity in 2016, and Delphi is more popular than Go and Objective-C.
I could be wrong, but I think the spike in Dart's popularity recently is mostly because there was a world championship in "dart" (the pub game) recently.
The primary goal of the TIOBE index is not to accurately measure language popularity, it's to increase the popularity of tiobe.com. And, at that, they're doing a great job.